Power supply circuits are widely used in modern electronic devices, providing power voltage signals to enable function.
A conventional power supply circuit usually includes a voltage conversion circuit converting a primary voltage to an output voltage for a load circuit, a feedback circuit feeding back the output voltage, and a controller controlling a working state of the voltage conversion circuit according to a feedback signal provided by the feedback circuit. In operation, when the feedback signal indicates that the power supply circuit is in an overloaded state, the controller immediately directs the voltage conversion circuit to stop functioning, and the power supply circuit enters a protected state, to avoid burnout.
The power supply circuit may suddenly enter instantaneous overload, for when the load circuit transits from one steady state to another. Such instantaneous overload normally lasts for a very short time, after which the power supply circuit automatically recovers to a normal working state. However, once the instantaneous overload occurs, due to the mentioned feedback signal, the power supply circuit may be forced to enter the protected state and stop functioning. In this situation, an electronic device employing the power supply circuit can shut down unexpectedly, affecting reliability of the power supply circuit.
What is called for is a power supply circuit that can overcome the described shortcomings.